Sharpening mechanism for cutting machines



July 29, 1952 F. e. CLARK SHARPENING MECHANISM FOR CUTTING MACHINES Filed Nov. 18, 1948 6 Sheets-Sheet l July 29, 1952 F. G. CLARK 2,604,741

SHARPENING MECHANISM FOR CUTTING MACHINES Filed Nov. 18, 1948 e Sheets-Sheet 2 IN V EN TOR. AM

July 29, 1952 'F. G. CLARK SHARPENING MECHANISM FOR CUTTING MACHINES Filed Nov. 18, 1948 6 Sheets-Sheet 5 INVENTOR.

GZ-Z'orneys.

July 29, 1952 F. e. CLARK SHARPENING MECHANISM FOR CUTTING MACHINES Filed Nov. 1a, 1948 6 Sheets-Sheet 4 y 29, 5 F. e. CLARK 2,604,741

SHARPENING MECHANISM FOR CUTTING MACHINES Filed Nov. 18, 1948 6 Sheets-Sheet 5 63 619 730 i 5 e5 I 2 A 720 76 l H 7 ?5 Q7 ll 7 l 727 7Z4 V Z92 /;?5

726 5/ f I 7Zg\\ J 5 I fig} 755 ll i" I 86 85 53 I 35 gg J I 759 a E1; 1% 750 757 I I, E I 9 7X 1 E 753 795 79 l m 73:? @s l In... 20 747758 .7 74 5 i I I k INV T Zwb W i atented July 2 9,

SHARPENING MECHANISM FOR CUTTING MACHINES Frederick G. Clark, Bufialo, N. Y., assignor to Eastman Machine Company, Buflalo, N. Y.

Application November 18, 1948, Serial No. 60,796

18 Claims. (Cl. 51-246) 7 This invention relates to knife sharpening mechanisms for cutting machines, and more particularly to mechanisms of this kind for use with portable cutting machines of the type commonly employed for cuttingcloth and other sheet materials, and which includes a reciprocating knife having a substantially vertical cutting edge.

One of the objects of this invention is to provide a sharpening mechanism with means of improved construction for reciprocating the sharpening devices along the edge of the knife. Another object is to provide a mechanism of this type in which the travel of the sharpening imp-lements lengthwise of the knife can be varied without the use of clutches. It is also an object to provide a mechanism of this kind with drive means of improved construction. A further object'is to provide a'mechanism of this type with means of improved construction for stopping the operation of the knife sharpening mechanism when its cycle of operation has been completed. Another object of this invention is to provide a sharpening mechanism of this type with means of improved construction for actuating a vertically movable bar by means of which the knife sharpening mechanism is' moved vertically from power'derivedfrom the flywheel or crank wheel of" the machine. Another object is to provide mechanism of improved construction for releasing the presser foot when the sharpening mechanism is used.

Other objects and advantages of this invention will appear from the following description and claims.

In the accompanying drawings:

Fig. 1 is a front elevation of a knife sharpening mechanism embodying this invention and detached from the cutting machine.

' Fig. 2 is a face view of a crank-disk employed in connection with this mechanism.

Fig. 3 isa rear elevation, partly in section, of

the mechanism shown in Fig. 1.

Fig. 4. is a transverse, sectional plan view thereof on line 4-4, Fig. 3.

Fig. 5 is a side elevation thereof, partly in section, approximately on the line 5-5, Fig. 1.

Fig. 6 is a fragmentary side elevation thereof, partly in section, showing the oscillatory bracket on which part of the drive for the sharpening mechanism isv supported.

Fig. '7 is a fragmentary, sectional elevation thereof. on line 1-1, Fig. 6.

, Fig. 8 is a fragmentary side elevation of the lower portion of a cutting'machine showing a sharpening belt carriage in a lowered position. -Fig. 9 is a top plan view of the belt carriage shown in Fig. 8, with some of the parts shown in section.

' Fig. 10 is a fragmentary. side elevation thereof. Fig. 11 is a fragmentary, front elevation of a knife sharpening mechanism of modified confstruction. Y

Fig. 12 is a fragmentary side elevation thereof. Fig- 13 is a fragmentary, sectional front .elevation thereof showing a mechanism forreleas ing the presser foot when the cutting'mechanism is to be used. ff Fig. 14 is a view similar to Fig. 13 showing the parts in position for holding the presser 'foot'in operative relation to the work.

Fig. '15 is a sectional view thereof, l5-l5, Fig. 14. Fig. 16 is a fragmentary front elevation of .part of the mechanism for moving the knife sharp ening carriage. p

The cutting machine in connection'with which my improvements are used may beof any suite able, well known type, and consequentlyponly parts of the cutting machine are shown in the drawings. V I

The cutting machine includes a base l4, shown in Fig. 3, which is movable un the surface on which the cloth or other material to be cut is supported, and a, slender standard l5 extends upwardly from the base and is secured at its-lower end to the base and supports the motor (not shown) and other mechanism of the cutting'machine, including a connecting rod or pitm'an-Hi, Fig. 5, which reciprocates a knife 11. The front of the standard is provided with the usual guide means for the knife H. i8 represents a. presser foot which bears on the top surface of the material tobe cut and which has a slot or recess therein within which the knife reciprocates. The presser foot is attached to an upright rod I 9 by means of which it may be adjusted to the desired elevation. This rod in the construction shown is square in cross section and is provided with teeth or projections with which a, toothed I on line end of a presser foot locking bolt [9a may e'ngage to hold the presser foot at the desired elevation above the base M, as is customary. in cloth cutting machines, the bolt l9a being slidably mounted on the frame 20 of the cutting machine to guide it into and out 'of'locking position, and being actuated by the operator through the medium of a hand lever [9b. A part only of the frame 20 is shown in Fig. 5, within whicha motor is mounted for reciprocating the knife l1, this motor including a crank wheel or flywheel 2| to which the connecting rod or pitman Isis connected. This pitman cooperates with a crosshead 22 for transmitting reciprocatory motion to the knife. I1. 1 The knife sharpening mechanism embodying this invention is enclosed in and mounted'on a suitable housing 25 which maybe secured to-the cutting machine housing 20 in any desired manner, for example, by means of bolts or screws 2 shown in Figs. 1 and 3. The sharpening of the knife, which may be accomplished by any desired type of grinding devices, is preferably effected by means of belts 28 and 29, each having one face thereof coated with suitable abrasive material. As usual, these belts operate over driven pulleys 30 and 3|, Figs. 1, 8 and 9. The belts also pass around idler pul= leys mounted to rotate ona suitable belt carriage 34 which is arranged to move up and down lengthwise of the knife so as toenable the knife edge to be sharpened throughout its entireler gth by contact with the abrasive surfaces of the belts 28 and 28. 35 represents a guide member mounted on the belt carriage and cooperating with the rear edge of the standard l for guiding the belt carriage in its vertical movement. Since 'belt carriages of this type are well known, a more .detailed description of the same is not d medpeces a y- ""The' driven pulleys -30 and-3| are suitably securedto 'theilower' ends of vertical-shafts 36 and 31. These shafts are preferably square or rectangular in cross section, or may be splined, andaremounted to slide vertically through gears 38 and '39 respectively and to rotatewith these gears. The upper ends of these shafts are suitably guided on the frame 25 for axial movement. These shafts may, for example, be guided 'as.shown in my Patent No. 2,537,208 of January 9, 1951. According to this application, these shafts extend into guide tubes 48 and 4| suitany secured on the housing 25, and each shaft ,islprovided with .a follower 42 on the upper end thereof. These followers are preferably rigidly secured to the upper ends of the shaft, for example, by means of threaded ends on the shafts ,grtending intoth'readed holes in the followers, and the followers have a sliding and rotatable fit Lwithin the guide tubes 4| and 42, so as to hold thefshafts in correctrelation .to each other and the gears 3,8 and 39 which mesh .with each nths The shafts 36 and 31 receive rotary motion .from a drive shaft 44 suitably journalled on the housing 25, and having a gear 45 secured to the lower end thereof which meshes with the gear .38, and thus supplies power and rotary motion to both of the drive shafts for driving the knife harpening belts 28 and- 29. The drive shaft 44 is driven from thefiywheel 2| by means of a drivenwheel '41 which is suitably journalled on a bracket 48 pivotally mounted on the frame 25, in such .a manner that the wheel 41 can be moved into and outof engagement with the flywheel 2|. The wheel 41 may be provided with the usual rubber tire or band for'providing the desired friction for driving the wheel 41 from the flywheel;

The wheel 41 is mounted on a shaft 50 which is glournalled in suitable bearings 5| on the brackt 48 .and the shaft 58 has a gear'52 mounted thereon which drives a gear 53, both of these gears preferably being spiral gears. The spiral gear 53 drives a spiral pinion 54 secured to the drive shaft 44. The spiral gear 53 is journalled to rotate about a pin 55 secured to a lug or projection 56' of the frame 25, and this pin also serves as a pivot on which'the bracket 48 is mounted to swing to a limited extent to move the wheel 41 into and out of engagement with the flywheel 2|. Consequently, when the wheel '41 is in frictional engagement with the flywheel 2|,the drive shaft'44 will be rotated to supply power to the shafts 36 and 36 on which the abrasive belt pulleys are secured.

' Means of improved construction are provided for producing reciprocatory motion of the car riage 34 on which the knife sharpening belts or other implements are mounted, andin the particular embodiments the'invention illustrated in the drawings, the power for reciprocating the carriage is also derived from the drive shaft 44 which is provided near the upper portion thereof with a worm 60, see particularly Figs. 1, 3 and 5, which engagesa worm wheel 6| secured to a shaft 62 journalled on the frame 25. The shaft 62 has a gear wheel 63 secured on the other end thereof which drives a gear 64 journalled on a bearing pin 65 secured to the frame member 25. This gear 64 has secured thereto a crank disk 66 which has a crank pin 61 secured thereto on which one end of a pitman or-walkingbeam 68 is pivotally mounted. The pitman or walking beam preferably has an enlarged upper end -portion-69 which is apertured to receive the crank pin 61. Consequently, it'will'be-obvious that when the crank disk 66 is revolvedbymeansof the gear 64, a motion of translation in a circle will be imparted to the end 69-of the pitman.

The motion imparted to the pitman 68 may be transmitted in any suitable manner to-the belt carriage 34. In the construction illustrated-for this purpose, the pitman 68 is in the form of'a rack having teeth formed on one edgethereof.

The teeth of the rack of the pitman-'68 engage a pinion 1| rotatably mounted on a stud'12, the inner end of which is secured to the frame member 25, and another gear 13 is-rigidly secured to the pinion 1| to rotate therewith, and this larger gear 13 meshes with rack teeth 15 formed on a vertically movable bar 1.6, the lower, end of which is rigidly secured to the belt carriage 34, forexample, by means of a clamp 11. It will thus be noted that as the crank disk 66 movesfrom the position shown in Fig. 1, in a counterclockwise direction, the rack bar 68 will be moved into various angular relations, but in a generally downward direction, and this results in the rotation of the gears 1| and 13 connected thereto in such a manner that the vertically movable rack bar 16 will move downwardly, and when the crank disk 66 continues its rotation and returns to the position shown in Fig. 1, the gears 1| and 13 will be rotated in the opposite direction, thus raising the rack bar 16. 11a represents a slide bearing secured .to the housing 25 and having a U-shaped part in which the rack portion of the pitman 66 is guided for vertical movement, a portion ,of the U-shaped part being cut out as shown at 18 to enable the-gear 13 to engage the teeth of the rack bar.

The pitman or. rack 68 may be heldin operative relation to the pinion 1| in any suitable or desired manner, and in the construction shown for this purpose in Fig. 1, a link ispivotally mounted at one end thereof on the bearing pin 12 and has-a grooved pulley or wheel 8| pivotally mounted on the other end thereof. This wheel is formed to engage the back of the rack 68 .and thus holds it in engagement with the gear 1|. As the pitmanor rack 6 8, because of its direct driving connection with the crank disk .66, assumes various angular positions, the link 86 will swing about the bearing pin 12, so that the grooved wheel 8| will at all times remain in engagement with the back of the rack 68, and consequently, always hold this rack bar in operative relation to the pinion 1 Since cutting machines of the type described may be provided with knives of many different lengths, it is desirab e o provide su table mea may receive the threaded end of the crank pin 81, so that the length of the stroke of the pitman or rack 68 may bevaried as desired. When any of the holes 83 is selected'for obtaining the desired movement of the belt carriage, the gear 64 may-be rotated while the rack or pitman 88 is disconnected therefrom to occupy a position at one end of the stroke of rack bar 16, and the link 80 may be released by removing the bearing pin 12, so that the pitman 68 may be moved'into proper engagement with the teeth'of the pinion 1I, so that the proper gear relationship is established to provide the correct movement of the rack bar 18. When it is necessary to connect the pitman 68 through the crank pin 61 with apertures nearer to the center of the crank disk 66, this crank pin may be passed through additional holes 84 in the enlarged part 69 of the pitman, so that the outer end of the enlarged part may extend somewhat beyond the periphery of the crank disk when the same is in the position shown in Fig. 1, for reasons hereinafter explained. Any other suitable means for varying the length of the stroke of the pitman or rack 88 could be provided if desired.

The swinging of the bracket 48 to move the wheel 41 into and out of engagement with the flywheel may be effected in any suitable or de-- sired manner and preferably the mechanism. for accomplishing this result is so constructed that the bracket 48 will be returnedto an inoperative position in which the wheel 41 is out of engagev ment with the flywheel by means of the pitman '68 when the same has completed one cycle of movement and the carriage 34 has been returned to its upper position. In order to accomplish this result, the pivoted bracket 48 is normally urged,

' for example, by means of a spring 85 into a position in which the wheel 41 is in engagement with the flywheel 2|. One end of this spring shown engages the'bracket 4B and the other end thereof bears against a screw 86 engaging the threaded holein the rim or flange 81-of the frame member or housing 25.

The bracket 48 is provided with a rigid or integral extension 88 projecting toward the front ofthe' machine and an arm 89 is pivoted on a pivot pin 90 on the bracket 48. For this purpose; the arm 89 preferably has a downwardly extending ear or lug'9I on one side thereof and a flange 32 on the other side, the pivot pin extending through the lug and flange. The flange 92 may engage a side of the extension 88 and a portion of the-armextends forwardly beyond the extension 88, as clearly shown in Fig. 6, into position to be engaged by the head or enlarged end 69 of the pitman or rack 88.. The arm 89 is normally held in its lower position in the path of movement of the part 69 of the pitman by means of a spring 93, one end of which engages a screw 94. This screw engages a threaded hole in the extension '88 of the bracket 48, and another screw 95 in this extension may be provided to limit the extent to which the arm 89 is urged downwardly by the spring 93. The upper part 89 of the pitman or rack, consequently, normally holds the bracket 48 against the action of its spring 85 in a position in which the wheel is out of engagement with the flywheel 2 I. When it is desiredtd start the cycle of movement of the sharpening mechanism, the arm 89 is moved upwardly by hand against the action of the coil spring 93 to permit the pitman or rack to disengage the arm 89, whereupon the spring will immediately swing the bracket 48 into a position in which the wheel 41 engages the flywheel 2|, whereupon the mechanism will begin to operate, rotating they drive shaft 44, the shafts .36 and 31, and the gearingwhich turns the crank disk 65. The arm 89 may thenbe released, whereupon it willbe I moved by the spring intothe path of movement ofthe part '69 ofthe. pitman 8-8. ,Upon completion of the cycle of movement of the carriage against the action of the spring 85 into a position in which the wheel 41 is out of engagement with the flywheel 2I. The mechanism is thus brought to a stop and the bracket will be held in its inoperative position until the arm 89 is again raised.

Since the knife 7 I1 reciprocates during the sharpening of the same, the lower edge'of the. knife will pass upwardly above the lower; belt 28, when the belt carriage is near the lower end of its stroke. I have, consequently, provided means for movingthe portion of this belt which engages the knife laterally to clearfthe knife when the belt carriage is, in the lower portion of its movement. In this connection, attention is called'to the. fact that the inner faces of the belts 28 and 29 pass into engagement with shoes I08 and IDI which are yieldingly, mounted to urge the belts 28 and 29 into engagement with the edge of the knife, these shoes being pivotally mounted. on pins or. bolts I82 and H13 hub I I0 secured thereto and an arm III projectsfl outwardly from this hub and has a part H2; bent at "a right angle thereto intopositionto engage an upper flat surface H3 of the presser foot. It will, consequently, be noted that as the belt carriage approaches its lower position as shown in Fig. 8, the arm III will be swung upwardlyby engagement with the upper face of the presser foot into the position shown in broken lines in Fig. 8. This movement of the arm causes rotation of the cam I85, so that the cam engages the extension I04 of the shoe ,Illil,

and moves the same-in the direction away from the knife edge. Consequently, during the lower portion of the movement of the belt carriage only the. upper belt 29 will engage thelower portion of the edge of the knife and when the knife moves downwardly, it will clear the lower belt 28 and thus eliminate the possibility of damaging this belt as the belt carriage rises, the arm III will again be urged to swing downwardly by means ofra spring II5, Figs. 9 and 10, thus returning the shoe I00 into position to press the.

belt 28 against the edge of theknife blade. A

.pin 8 on the belt carriage 34 limits the extent to whichthe arm II I may be swung by the spring I I 5, so that it will be in correctposition to again;

H as :the

in mesh at all timesand no. clutches are necessary. .1;

to reverse the: m0tion1:of-.:the i-helt :carriage, :thus eliminating difiiul'tiesi heretofore encountered. with the failure ofiiclutch'es to". operate. The-- sharpening mechanismihasthefurther advantage that the wheel ."isls'positivelyz moved-rout oftfrictionalzenga'genient.with the'flywheel by means of the engagement otjthe rack .68.' with.'the--arm 89,-? thus providing :a very effective land relatively inexpensive constructioniwhichl isuvery positive v in'its--operation.

Themounting offi'the wheel. 41 on a=-pivoted bracket in such a manner that the wheel 4'l"canswing into en'gagem'ent 1 with the; flywheel; as :shown 'alsoh'astht advantage: that the? wheelAI engages the flywheel -with 'a certainf' amount'iofwedging'ortoggle action; dueztoith'e -:rotation of if the flywheel inf: the directioniiindicated by, the arrow' imFig. o '-that--comparativelyrlittle pressure is requ' ed' for th springa85itozholdithe bracket 48 in position in '.-which tovdrive the wh eel fl-F- Sinoe -very little pressurexzis .required. on the part "cf the 'spring 85; it also follows-that: comparatively little forc'e 'is requiredi to :hold the bracket-in its inoperative positicn;

InFigs- II," lzand 16- is shown amechanismaof modified c'onstruction for moving the/"rack bar 16 on-which the belt 'carriagei 34s is mounted (up; and down to' effct sharpening goiithe knife,-:the mechanism 'for 'driving the belts andxior :swinging the bracket: 48 't0 move thecwheel: 41, into anda out- 0f engagement witlr the flywheel ibeing'gthe" same *asillustrated in connection with.-;Figs. i 1 1 to -105- In this eon'sttucti'on'; ascrankzwheel' It'd- 5;.

crank pin I 2 I adjustably mbuntedrither'eonm aim-:5 i

crank pin -l 2 [is secured o'n a disk IZZeccentricalr-I ly*-pivoted on=the= crank" wheel'stbyrzmeansvofw a screw I 24 -which may be ti'ghtenedzltotclampg the disk tothe 'crank wheel. Th'e disk I22'iinay:;be readily" adjusted about 'the screwli I24 zwhem the same loosenedto move e'cranklpint I21 .there-:. on-into difierent-"relatio'ns with reference-to: the; axis'of the crank wh'eel lfl and-additiOnahmeanS are prferably 'providedtor securing Lthis':disk':* I 2 2 in any positionxi'n which it. maybe i' set;-

- theeonstr'uction shownfcr thislpurposaathezniskr is' provi'dedwith gear teeth onfiits peripherytrand: afpair'pf 'pmions =I 251T and I 2 G are imountedpion': the-crank wheel by' meansof screws l2'lv'a-ndil28'? engaging in f threaded 'holes -in the crankiwheer- I205 These piniof'n's are so mounted 'thataby; tightening "the "screws I I 21 fand l 28, the pinions'i may be 'locked against rotatidnfi Ciinse'quentlw ifitis-dsired t adjust' tl'l' thiow of the icrank" II TF the scr'evvS 'I Z r; I Z'l and a' ar' zlo'osenedl Wpermn the eear wneer I zz-zdarrym' smb crank; rs

I2Ii to be-turnedaboutitsaxis .andwhenthe desired! :adjustment has been 1 made, .th e screws I 245 I 2] *andg I 28 i are: again tightened to prevent turning of the 'pinions. I25 and I26; and of the crank'diskini 1 The crank-HI is shown inFig'.- 11 as. adjusted: for-the ,maximumthrow andinl. Figs.16,1this.- crank--pin I2I is adjusted for. a.. smalleriithrowz" Thisiconstruction, consequently, replaces thez disk-:BB -shown in Fig; 2 for varying the: throw 'of ,thescrank by securing the crank pin i-inone or other-of "then-threaded holes 83 therein H v. V

138 represents. thepitman; which is. pivoted adjacentcto-one zendithereofon: the crankpin .I 2 l v andiwhic-h; has; an upwardly projecting. end.

forme-dnto :engage the arm .89 which is connected with' 'the .-bracket Aihto "swing the same -in..the

manner described-in connection with Figs... 1 .to I

ple as :the'pitman- I3I shown in Fig. 16 in which.

the saperture for the crankpinis located farther fr'omrtheiupper end thereof, since-the end of the pitmanebeyond the.-:crank-pin- I2I must at all.

times be longienough .to-aengage .the arm 89 of the pivoted: bracket 48.

Th other end. of the pitman -.I 30 is pivotally connected with-a. gear.-segment.-I 32 journalled inv a bearing ipin .l33isuitably secured 0n astatione ary'part .01": the frame of-the knife sharpening I mechanism, so that as the crank wheel I20 revolves-about tits Basis, theapitman imparts .an oscillatory motion to'the gear-segment 132. teeth of ithis gearsegment mesh with a pinion I3 5 irotatably; mounted Ion- 5a fixed bearing. stud. IBGsandranothengear I37 is rigidly secured to the. pinionwI35 to=-rotate therewith and meshes with Y the-mack teeth-.15 ofthe vertically movable'bar 1.16 .rwhi'ch carries the belt carriage. 34s It will,-

consequently-be" obvious when thearm 89 .connected with'the bracket 48-is raised to release-the second Wheel-.41: to-move intoengagement with thkifiY-WhEBlfithB crank-wheeHZIl twill-be turned through one revolution; causing .the pitman I30-- toze'scillate-sthe gear segment I32 and through. the gearc I 31*itocaus'e .the belt carriage .to be moved downwardly;- andcthen upwardly for sharpening the knife;

the knifeyand also-that thedwell or time during, which there. ishvery little-movement of theknife carriageatthe lower end'of the stroke-is reduced,

thus reducirigxthe tendency'of the sharpening.

mechanismto roundbff. the lower end or point of the knife; I

1 Means a b'olt lea is' slidablyiarranged on the frame of the machine soithat thetteeth'or projections on the end thereof may move into and out of mesh'with' the teethz-i 4o *ofrthe rodfl 9 "for holdingthe me. iniany' positibnlin"which it"may beset by the operator," see :alsoJFi'g. 1, in: which this locking-1;

bolt? is shcwn1rfornmanual operation.-

Thebuteniend ofathe ilocking. bolt I Saris-b The ThE-IcOIlStIllCtlOn shown in Figs. 11, 12 and..16"

also lprovided bin the construction shawl-i intFi'gSzzll tor-l6 -for automatically, releasing th presserrfoottwhen the knife sharpening m'eehanismiiis i placed. into operation and this. mechanism may, of 'course, also 'be appliedto-the construction showninzFigs; 1 to l0'. .The locking iturcate'd a's shownat 'I 43'and the manually operated; leveraI-Sb is :pivo'tallyi mounted between a pair-pt.

- lugs I45 on the machine frame 20 by means of a pivot pin I46 and has one end portion thereof extending into the bifurcated end of the locking bolt I9?) and is pivoted thereto by means of a pin I41. The end of this lever is provided with a handle portion I48 arranged in a positionconvenient to the operator for quickly shifting the locking bolt into and out of engagement with the rack teeth of the rod I8. A spring I50 normally urges the lever I912 into a position in which the locking bolt holds the bar I9 of the presser foot against movement.

In order to automatically shift the locking bolt into unlocking position when the sharpening mechanism begins to operate, means are provided which are actuated by the bracket 48 in such manner that when the bracket swings into position to place the wheel 41 into engagement with the flywheel, the locking bolt is Withdrawn from engagement with the rod l9. In the construction illustrated for this purpose, a lever I53 is provided which has a hubportion I54'piv'oted concentrically with the axis of the crank wheel I20, for example about the axis of this crank wheel, or on the hub of the gear 64 when this mechanism is employed on ,the construction shown in Figs. 1 to 10, and this lever has an arm 155, which bears. against an edge of the arm 89 of the bracket 48 in the same manner as the pitman I30, except that the arm I55 bears against the arm 89 at all times. The lower end I58 of the lever I53 hasa tongue 'or projection I51 which extends between a bifurcated end I59 on the end of the hand lever I91).

In the operation of the presser foot releasing mechanism, when the arm 89 is raised to release quently, this'locking arm is swung by the action of the spring 85 into the position shown in Fig.

13, thus releasing the presser foot rod l9 so that the same either falls by gravity to its lower most position, or else is pushed into its lower position by the operator or the belt carriage 34. The automatic mechanism, consequently, prevents the possibility of damage to the presser foot or knife sharpening mechanism due to operation .of the sharpening mechanism when the presser foot is locked in an upper position, and relieves the operator of the necessity of lowering the presser foot before the sharpening operation begins.

7 It will be understood that various changes in the details, materials, and arrangements of parts which has been herein described and illustrated in order to explain the nature of the invention, may be made by those skilled in the art within the principle and scope of the invention, as expressed in the appended claims. I

I claim as my invention:

1. In a mechanism for sharpening the edge of a a knife of a cutting machine, comprising knife grinding means, driving means therefor, a carriage for said grinding means arranged to travel lengthwise of the knife edge for presenting the grinding means to different portions of said edge, and a bar slidably mounted on said cutting machine and secured to said carriage, that improvement which comprises a rotary crank, a pitman connected at'one end thereof with said crank, means driven by said pitman and engaging said bar for reciprocatingthe same, and mechanism v.10 actuated by said pitman for interrupting movement of said pitman when said crank has completed a revolution.

2. In a mechanism for sharpening the edge of a knife of a cutting machine having a reciprocatory ,knife actuated by a flywheel, and comprising knife grinding means, a carriage for said grinding means arranged to travel lengthwise of the knife edge for presenting said grinding means todiiferent portions of said edge, and a bar slidably mounted on said cuttingmachine and secured to said carriage, that improvement whichincludes a pivoted brackethaving a wheel mounted thereon which is movable into and outfof engagement with said flywheel when said bracket is swung about its pivot, a rotary crank,'gearing connecting said second wheel with said rotary crank, mechanism connecting said crankwith said bar for, reciprocating the same, and a part associated with said crank arranged to engage a part of said bracket when said crank has completed a revolution to move said bracket into a position in which said second wheel is out of engagement with said flywheel.

3. A knifeedge sharpening mechanism according to claim 2, in which saidpart on said bracket is a pivoted arm yieldingly urged into a position to be engaged by said part associated with said crank and which arm may be swung about its pivot to disengage said part associated with said crank to permit saidv bracket to swing intoY-a position in which said second wheel engages'said flywheel, to, start a cycleof operation" of said sharpening mechanism. 4. In a mechanismfor sharpening the edge of a knife of a cutting machine having a flywheel and comprising .knife. grinding means, a carriage for said grinding means mounted to travel lengthwise of said knife for presenting said grinding means to differentportions of said edge, that improvement which comprises a bracket having a second wheel ,journalled thereon, a pivot. about I which said bracket may swing. formovingjsaid gear mounted thereon meshing with said first mentioned gear for rotating said drive shaft, mechanism actuated by said drive shaft for operating said knife grinding means, meansfor swinging saidbracketabout its pivot to movesaid second wheel into engagement with said flywheel,

I a pitmanpivotallyconnected at one end thereof eccentrically. with said second wheel, mechanism including a rack connected withv said carriage and a gear meshing with said rack for reciprocating said carriage and. actuated by said. pitman, and means associated with said pitman for actuating said bracket tomove said second wheel .out of engagement with said flywheel.

5. In a mechanism for sharpening the edge of a knife of a cutting machine, having a flywheel and comprising knife grinding means, and a carriagefor said grinding means mounted to travel lengthwise of said knife for presenting said grinding means to diiferent portions of said edge, that improvement which comprises a bracket having a second wheel J'ournalled thereon, a pivot about which said bracket may swing for moving. said second wheel into and out of engagement with said flywheel, a pinion rigidly securedto said second wheel; a gear rotatable about said pivot .andmeshing with said pinion, a drive shafthaving a gearjmounted thereon meshing with said ,jfir'st mentioned ar for rotatinas i flrive.sh i yielding means for urging saidlbracket to swing in, a irection; in which, said, secon Wh g aa'es.saidgfiywheeln acrank r tate by mean connected to saiddr ive,shaft, a;pitman connected iatg mecnd with said cranka rack connected with d .carnia e, a gear.v meshing, with said -rack,; a connection. between,v s i pitman and; d e .eforgalternately turning said gear; in oppositejdiirri ations. to, reciprocate, said. c rria e, me associated yvith .;.said ;-pitman'1 f mm ine sa bracket a a nst thelactionbisaid yield nein a s *te'fmove. ,said, second wheel, out of en a eme -wl-ithcsaidlcflywhee 6;;In amechanism"iorsharpen n 'the edge, o kni of ,cuttin machines. compr sin .km'fe xindinam an dr vinamca stherefori eludin 'i stwhee from'whic ,,nower sgde ved;turnpratin ;saidgerindin meansean ,a arria e-to :iwisei fisaidknii .ed e. presentin sa dygrin Qinameans t different. po tion 'tofrsa d dea th improvement which-,cornprisesa rotarycrank, a nitmanoonneded eat. on end w th sa crank,

lconnectmg m ansi etw e i saidpit am d an ;,riage for movingsaid .carriage lengthwise. of said kn .:ec1g a v ed'rbrac i having a seco ,whcelJ urnaHed:thereqn'for mov me int and out of fdriving, engagement with said "flywheel,

; means eonnectingsaid. 'crankruand 7 said second" twheeL for rotating. said crank, .meansgfor, yieldinglynrging said bracket into a; pgj'si'tionlin' which said second wheel contacts, said iflywheel to reme y p wer there rom. jandtmeans a tua d y ,-.saidinitma .idnr ns;themoremm t he sa wi h-:sai rra iionmovm isai b ack t n a gpo si io ii .;wh s s i secon -wh eli uteo we easement-wit ;saidiflvwheek'fm. nterruptin emovement o said car ia e- I a mecha ism; for. ls ar en ne the; ed o aak it io a uttin ,im chin ihavin ga"flywhe eand; cam r sinc knife; eri idmameanaandaoa agetfonsaids in inemea sm untedt itrav len thwis iof sa kni jfpr presentin s i idins mean .t nif e entp rtiqns of said ed e,

Ethatimnmwmen whic comp ses a i brac et ihavinea eca dwhcel i urna ed thcre aa pivot ,eabout which saidhracke ma swineionmwine sa d sec n vi eelgint iandlQut of en a ement w thsaid flywheel, d v .shait, ea in ico 2 meetin saidsecon whe l and. sa d ldr ve sha *tfc rotat n thesamew ensam.secon wheeiis iimenea eme t .withi ai iflyw eel,., a 0- 1' tatedbysai jdr ve ;shai .m.eans,actu tedby sa ;r cra kffo mparti rec proc tqrym t o ztds i carria e, a part. mo abl moii ted on. sa d ra k t, anda part on, sa d cmnkfsnmed t e eae jsa d part n said bra k when. sa d-c an hasv moved tliroueh a r volution; to m re saidbra' ketintq a "position in whichsaid secondwheel out of en- \60 saeement with said fl whee f 'I. -.".In a mechanismfo isharneni s' th edgeof a lknifegofa cuttinemaqhine hayinaaf wheel and icomnrisin knif riridinameam,=andpagca ria e iiprrs idgriridingmeans ounted t t vellen t 65 wisehofl said knif Q-fQr, presentin sa d, rinding means; tqLdiiierrzntpoittions of sai'diedge, thateimm vement which.comprise ...b aeke hav n a second 7' wheel .journalled thereon a pivot about gnvhich, said bracket .-.may swing for. moving. "said ssecondvwheel into -.,and, out of ,lenga ement, with 1 fisaidtfiywhe 1-,.,a. drive, shaf gearin -{c nn tin ,saidisecond .wheelland said .drive. shaftjor, ,ro-

engagement with said flywheel, a crank rotated aid grindin meansaa ran edtmtr vfl .1e et lengthwise of the knife edge'for" presenting the *5 a position in which said second wheel engages said -flywheel, and a part on said bracket extend- 'ingintor the path of movement of said pitman when the'same has-been moved by a revolution" of "said crank,1for shifting saidbracket against said l0 v yielding means intoa position inwhich said second wheel is out of engagement with said -fly- .wheel.

'1 9; In a mechanism for sharpeningthe edge ofa knife ofa cutting machine having a flywheel and l5 7 comprising knife grindingmeans,- and a carriage for said grinding means mounted to travel lengthwise 1 of said ,knife for presenting said grinding means: to -difierent portions; of the edge; of-said knife, :that "improvement which comprises;- a

0 r, bracket having a second wheeljournalled there- .7 on a' pivot about which" saidbracket may-swing for moving said second wheel into andout of en- ,gagement withsaid flywheel,- a drive shaft,-g e aring connecting said second-wheeland said drive shaftfor rotating the same when saidsecond aipart connected with said, crank formed to engage said. arm when said crank, has been moved through a revolution, to'movegsaidbracketjnto a position in'which said secondwheelis out of engagement with said fiywheeL; :said arm-"being rno,va ble manually relatively to said bracket to 40 ;10. A ;sharpening mechanism for ,cuttingmachines, according to claim, 9,'in which saidiarm ,is,pivote d on; said bracket and. is yieldingly-held in operative relation to said part connected with said crank and may be swung manually about its pivota1 connection with said bracket outofengagement with said partto' start the cycle of operation of said sharpeningmechanism.

ll. A sharpeningmechanism'for cutting ma- I chinesaccording to claim 9, characterized in that said part connected withsaid crank is a pitman which is'connected atoneend thereofto said crank, and ,in whichsaid arm is en a ed bysaid pitman to move said bracket into .an inoperative position.

12. In a mechanism for sharpeningthe edge of .a' knife of cutting machines comprising, knife 7 grinding means, ,drivingmeans therefor, acarriage' for said grinding means arranged to travel lengthwise of the knife edge'for presenting 'the grinding means, tQdifferent portions of saidedge, and a bar 'slidablymounted on-saidcutting machine and securedto said carriage, that improvement which comprises 'rackteeth on'said bar, a ,gear meshing with said rack. teeth, ,a pinion of materially smaller 'diameterythan said geariand secured to' said gear, a ;gear segment meshing with said pi ion, a rotary crank ;driven"by' said "machine and a pitman pivotally connected at one end withsaidcrank and at theother-endgwith said s me t- 13; In ame'chanism-for sharpeningythe edge of ,aknife of cutting machines comprising knife grinding means, driving means therefor, a cariaee: for: said grinding means arranged to, travel grinding means to different portions of said edge, and a bar slidably mounted on said cutting machine and secured to said carriage, that improvement which comprises a rotary crank driven by said machine, a pitman connected at one end with said crank, rack teeth on said pitman, rack teeth on said bar, a pinion mounted to rotate about a fixed axis and meshing with the rack teeth of said pitman, a gear of materially larger diameter than said pinion and secured in fixed relation to said pinion and meshing with the rack teeth of said bar, said pinion and gear being alternately turned in opposite directions when said pitman is actuated by said crank, to reciprocate said bar for imparting reciprocatory motion to said carriage.

14. In a mechanism for sharpening the edge of a knife of a cutting machine having a reciprocatory knife and including a presser foot movable in advance of the knife, knife grinding means including upper and lower abrasive belts arranged one above the other, a carriage for said grinding means arranged to travel lengthwise of the knife edge for presenting said grinding means to different portions of said edge and a shoe for each belt yieldingly urged into position to move portions of said belts into engagement with the knife, that improvement which includes a cam arranged in operative relation to the shoe of the lower belt, a rod pivotally mounted on said carriage and connected with said cam and having a part extending into engagement with said presser foot when said carriage approaches the lower portion of its movement, to move said cam into a position to move the shoe of the lower belt out of engagement with said lower belt to release the same from engagement with said knife during the lower portion of the movement of said carriage, and resilient means for returning said rod and said cam into positions to release said lower shoe when said carriage moves upwardly from its lower position.

15. In a mechanism for sharpening the edge of a knife of a cutting machine having a flywheel, knife grinding means movable vertically lengthwise of the knife for presenting said grinding means to different portions of the edge of the knife, a presser foot secured on a rod movable vertically on the machine, and a, locking bolt adapted to engage said rod for holding the same against movement, that improvement which comprises a bracket having a friction wheel mounted thereon and movable to place said friction wheel into and out of driving connection with said flywheel, and means connecting said bracket and said locking bolt to move said locking bolt out of engagement with said rod, when said bracket is moved into position to place said friction wheel into engagement with said flywheel.

16. In a mechanism for sharpening the edge of a knife of a cutting machine having a flywheel, knife grinding means movable vertically lengthwise of the knife for presenting said grinding means to different portions of the edge of the knife, a presser foot secured on a rod movable vertically on the machine, and a locking bolt adapted to engage said rod for holding the same against movement, that improvement which comprises a bracket having a friction wheel mounted thereon and pivotally mounted to move said friction wheel into and out of driving engagement with said flywheel, and a pivoted lever having a part which engages said locking bolt and another part engaging said bracket and which lever is swung by said bracket to move said locking bolt out of engagement with said rod when said bracket moves into position to place said friction wheel into engagement with said flywheel.

17. In a mechanism for sharpening the edge of a knife of a cutting machine having a flywheel, knife grinding means movable vertically lengthwise of the knife for presenting said grinding means to different portions of the edge of the knife, a presser foot secured on a rod movable vertically on the machine, and a locking bolt adapted to engage said rod for holding the same against movement, that improvement which comprises a pivoted bracket having a friction wheel mounted thereon, said bracket being movable into and out of an operative position in which said friction wheel is in engagement with said flywheel, a pivoted lever having one arm thereof engaging said locking bolt and having the other arm engaging a. part of said bracket, a spring urging said bracket into position to move said friction wheel into engagement with said flywheel, a second spring weaker than said first spring urging said locking bolt into locking position and said lever into engagement with said part of said bracket, and means actuated upon completion of the cycle of movement of said knife grinding means for moving said bracket into inoperative position, said bracket when moved by said first mentioned spring into operative position swinging said lever into position to move said locking bolt out of locking engagement with said rod.

18. In a knife sharpening mechanism for cutting, sharpening the edge of a knife of a machine comprising knife grinding means, driving means therefor, a carriage for said grinding means arranged to travel lengthwise of the knife edge for presenting the grinding means to different portions of said edge, and a bar slidably mounted on said cutting machine and secured to said carriage and provided with rack teeth, that improvement which comprises a rotary crank driven by said machine, a pitman connected at one end with said crank, a gear meshing with said rack teeth, and a pinion secured coaxially to said gear and of materially smaller diameter than said gear, and an operative connection between said pitman and said pinion for alternately rotating said pinion in opposite directions for reciprocating said bar and said carriage.

FREDERICK G. CLARK.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 183,061 Locke Oct. 10, 1876 1,004,285 Maimin Sept. 26, 1911 1,471,667 Litot Oct. 23, 1923 1,564,574 Hunt Dec. 8, 1925 1,779,981 Nickerson Oct. 28, 1930 2,060,197 Greenbaum Nov. 10, 1936 2,156,798 Bangser May 2, 1939 2,183,786 Clark Dec, 19, 1939 2,183,787 Clark Dec. 19, 1939 2,183,788 Clark et al. Dec. 19, 1939 2,244,813 Tommerup June 10, 1941 2,281,023 Clark et a1 Apr. 28, 1942 2,295,654 Gury Sept. 15, 1942 2,300,534 Clark et al Nov. 3, 1942 2,300,535 Clark Nov. 3, 1942 2,411,851 Caserta Dec. 3, 1946 2,529,441 Zawistowski Nov. 7, 1950 

